AVS 49th International Symposium
    Applied Surface Science Friday Sessions
       Session AS+MM+BI-FrM

Paper AS+MM+BI-FrM9
Voltage-Dependent Assembly of the Polysaccharide Chitosan onto an Electrode Surface

Friday, November 8, 2002, 11:00 am, Room C-106

Session: BioMEMS and Medical Devices
Presenter: R. Ghodssi, University of Maryland
Authors: L.-Q. Wu, University of Maryland
A.P. Gadre, University of Maryland
H. Yi, University of Maryland
M.J. Kastantin, University of Maryland
G.W. Rubloff, University of Maryland
W.E. Bentley, University of Maryland
G.F. Payne, University of Maryland
R. Ghodssi, University of Maryland
Correspondent: Click to Email
We examined the assembly of a basic polysaccharide - chitosan - from solution onto electrode surfaces as a result of voltage bias on the electrode. Chitosan is positively charged and water-soluble under mildly acidic conditions, and is uncharged and insoluble under basic conditions. We observed that chitosan is deposited from acidic solution onto the surface of a negative electrode and that the thickness of the deposited layer is dependent upon the deposition time, the applied voltage, and the chitosan concentration. No deposition occurs on the positive or neutral electrode. Once deposited and neutralized, the chitosan layer can be retained on the electrode surface without the need for an applied voltage. Infrared (FTIR) and electrospray mass spectrometry (ES-MS) confirmed that the deposited material was chitosan. The voltage-controlled deposition of chitosan provides a means for anchoring biopolymer material in specific locations in bioMEMS environments, such as encapsulated microfluidic devices fabricated in our laboratory using MEMS-based polymeric materials (EPON SU-8, Polypyrrole and Polydimethylsiloxane). Furthermore, chitosan's amine functionality should enable standard coupling chemistries to be exploited to anchor additional biomolecules (e.g. DNA and proteins) to the surface of bioMEMS devices.